Introduction: Neonatal and fetal mortality is increased in male fetuses. Evidence is emerging of sex specific differences in fetal and placental perfusion1. This study investigates effects of dietary intervention at specific time points upon blood flow and fetal growth trajectory in cattle.
Materials and methods: Primiparous heifers were either individually- (Australia, Au; n=360) or group-fed (UK; n=188) diets containing different levels of crude protein (Au, 14 and 7% CP; and UK, 18 or 10%CP) from 60 d pre-conception (fixed timed artificial insemination, FTAI) until 98 days post-conception (dpc) in a 2×2 design with diet changing at FTAI (UK) and 23 dpc (Au). Fetal development was assessed at 36 (crown rump length, CRL) and 60 dpc (biparietal distance, BPD) and Doppler-scanning of mid-uterine artery at 150, 180 and 210 dpc. Data was transformed and analysed using ANOVA for repeated measures.
Results and discussion: Diet change after implantation (23 dpc), rather than at FTAI, had a longer lasting effect on fetal growth (CRL and BPD, P<0.05). Preconception diet at 7% CP increased uterine blood flow (P<0.05), with the former reducing CRL (P<0.05) and BPD (P<0.05). Interestingly, post-conception diet also reduced CRL at lowest (7%; P<0.05) and highest levels (18%; P<0.05), irrespective of diet change time. Sex specific effects in preconception diets were observed, with male-carrying heifers showing an increase in uterine blood flow (P<0.05).
These results suggest that periconception diet influences oocyte and embryo development which may have long term and sex specific effects for the offspring.
Studies funded by S.Kidman & Co., Ridley Agriproducts, ARC and EBLEX.
Reference: 1. Prior T, et al. PLoS ONE 2013 8 (2) e56933.
02 - 04 Sep 2014
World Congress of Reproductive Biology